NEUROTENSIN-LIKE IMMUNOREACTIVITY IN LOCUST SUPRAESOPHAGEAL GANGLION AND OPTIC LOBES

A substance immunoreactive to antibodies directed against bovine neuro tensin (NT) was localized in neurons in the supraesophageal ganglion ( SEG) and optic lobes of larval and adult Locusta migratoria L. Two lar ge somata were located in the caudal cortex, ventral to the calyces an d symmetrical to the median of the SEG. Four smaller somata also in th e caudal cortex were located as two symmetrical pairs at the level of the central body. These somata formed a diffuse network of varicose fi bers from the superior lateral to the ventro-lateral protocerebrum bet ween the pedunculi and frontal cortical region. Some fibers crossed th e median to the contralateral sides of the SEG. Another pair of immuno reactive somata whose terminating processes remained unclear was found at the level of the antennal lobes. Intrinsic networks of fibers were labeled in the accessory medulla and in layer 4/5 of the medulla. The se fibers originated from 8-10 small somata near the dorso-frontal rim of the medulla. All larval stages contained these NT-like immunoreact ive structures. Results from isoelectric focusing and press-blot analy sis of SEG homogenates, synthetic neurotensin and neurotensin fragment s indicate that this substance is similar to bovine neurotensin(1-13).